Technological requirements for Space Station design were discussed. The requirements are discussed in relation to the following areas: high voltage arrays; environmental interactions; energy management; power supplies; architecture; and modularity

Smylie, R. E.

English

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SPACESTA110N]ECHNOLOBYPLANN!N6
R. E. Smylle
NASAHeadquarters
Bashtngton_ 0.C. 20546
I am certainly pleased and honored by the opportunity tO comeback and
speak again to a group that has been working together for so many years with 'i
great benefit to spacecraft technology and to the organizations represented.
Ha_y of you were here In 1976 at the first conference. Colonel-Brooke and [
spend a great deal of energy tn. those days trying to generate cooperative pro-
grams between NASAand the Atr Force Laboratory structure. Thts group is one
of the_many shlnlng exam;,les of success In that area.
,1
He both are proud of what we were able to set In motion tn those years.
There already was a great deal of interchange at the individual level, but tt
dtd not extend-as far- as It should have to gtve the maximumbenefit to both
organizations. He heve trled to establish not :}ust cooperative programs but a
spirit of cooperation amongthe people Involved tn technology programs all
along_the managementchain.
[ am going to Speak for a few mtnutes about space sta-Lton technology and
what NASAts pursuing tn terms of a space station program. It has long been
my belief that a mannedspace sta.tlon tn Earth orLtt Is almost an "_mperat_ve.
Nowtt Is not a matter of "tf," but a-matter of "when" and "what klnd" the
initial station w_11 be........
First, a few words about the Space Station Technology Steertng Committee,
o_ which I =m Chair. I _otned this organization _ust a few months ago. It had .
been chaired by Halt Olstad, who had been the Acting Associate Administrator of
OASTfor quite sometime. He movedover to be the Associate Admlntstr-ator for
I_anagement. Halt madesomema3or contributions to the committee, and I am
pleased to follow tn hts footsteps_._
He have In the committee a tremendous process by which to generate ideas
and plans for the technology we should be pursuing tn order to most benefit a
space station program once ttts begun. Each dtsclpl-tne area has a working
group that addresses the particular technology from that discipline that would
enhance a space statton program, etther through greater system performance or
through lowe_ life-cycle costs tn a program that would extend over many, many
years. Once t_e begin a space station programwe expect tt to conttnue Indefin-
Itely. It ma_,evolve - tn fact It w111 evolve - over time, but tt wt11 not
necessarily have a deftned endpotnt such as manyof our programs, Including the
Apollo Program and the Skylab Program, have had. A space station program ts
something that wtll continue into the foreseeable future.
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!Ihe Centers have assigned their most lnnovat%ve and competent people to
these work%.g groups, _o we get very good reports from them. Ou_ problem
becomesone of sorting out, from all of the good td_as, the ones that _hould
have the htqhest priority - the ones we shOu|d enact first tn _ space station
program _ an_ trying to combine them tnLo something manageable within a-budget
we m_ht oxpe_t to receive for thts pro_oct. The wor_of the Steertng Co.it
toe, then, ts to interact wtth the working groups and try to prtorltlze and
package the technology programs so that we can pursue them within our allotted
resources. Wealso must generate the data that will allow us to advocate those
programs through the management, 01_, and Congressional chaln_ In Order to
acq.tre the resources to do tttls important work.
In thi_ pro3ect there are somegreat technological opportunities to bone°
fit not only an evolutionary space station, but also an tntttal space station.
Usually you think of new technology as something tha_glves you greater per=
formance. In a space station program, once you have defined your requirements,
you want to meet those requirements at the lowest llfe..cycle cost.
Somepeople argue that we really do not need new technology to build a
space station. They say that we have, tn effect, created the equivalent of a ,i
space station tn Skylab and we have the technology from the shuttle program i
that wtll allowus to build a space station with whatwe have today. And that I
Is true. Ne could do that. But tt would be a shame If we dtd precisely that. I
If we are able to bring someareas of technology, particularly power and ther
mal to a state of readiness to apply to the first space station, that first
station w-ill actually be less expensive, both tn lnttlal cost and tn life-cycle
cost. He must verbalize thts messageand convey tt tn such a way that It ts
bel-teved_andwe can 9o ahead wtth tt.
He wtl] most 11kely pursue the space station program by using a modular
approach (ftg. 1). He belleve that the space shuttle will be the basis for
putting a mannedbase tn orbit; therefore the station will be butlt of modules
put Into orbit by the shuttle and docked to form a core. Other modules will
be added as the station evolves. There mayalso be platforms of various sorts,
either tn polar or tn low-Inclination orbit - probably both. These would be
tended by the space station. Somektnd o[ transfer vehtcle will be used to
movepayloads from the station to other orbits. A smaller device, called a
maneuvering system, w111 allow servicing of co-orbital platforms.
Figure 2 shows the types of equipment that may eventually be part of the
space station. The tnltlal station would be a core consisting of a power sys-
tem wtth a few modules attached to tt for experimentation In Earth orbit: a
co-orbiting platform for experiments that require very good stability; some
sort of maneuvering System that could tend the platform; and possibly a polar-
orbiting platform, the core station would evolve tnto something larger and
more capable over approximately 10 to t5 years, so a station after thts model
might be possible about the year 2000.
Ne are being careful not to produce a particular design before we have had
a chance to do a significant amount of concept development and Phase B studies.
So this ts really an artist's vision of what might be, not any particular
design that NASAts advocating. He try to define program requirements and let
those requirements drive the technology, rather than the other way around. We
• think that we should be tnvolved tn manyprograms at once but that there should
always be at least one program that ts sort of a "technology push." Nithtn a
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year or sO we would like t_ Qo into Phase _ studies toward the start of the
station tn a few years Therefore we need to pln down the requirements for
_ the _tatlon a_d de_Llr_.-th_ technoloQy tO be pursued
The first, requirement is that it be, a permanent system._one that you put
up and expect to use for-_ tong time. Thus we want It to be able to grow In
an evolutionary manner. Newtechnology will come alOnfl or requirements will
i _ , chanQefrom those _et 1_ the first years. It ts essentta.1 that tt can he rela _
ttvelv easily added to, _r changed, to incorporate products of the new techhol _
_ - ogy. Yuu want operat_o_l flexibility, because you really do not know r_ght
= at the hegtnntnQ all of the things you are gotn_ to use It for. 1he structure
Should be as flextble as posstble tn tts operation; tt should be multtplo use
i
Most of the purposes that the space statton might be destgned to serve
require high powe_across the hoard. No concept of a space station that I have
seen involves other than relatively high power, in the 50° to ?5-kW range.
• 1hat In ltself leads to a consideration of higher voltages than we have been
accustomed to using tn space 1he thermal loads w111 be large because of the
high power, and they will vary over an extremely wide margin With a human
presence, and the intention of using the station for manyyears, we wt_l most
_ 11kely want to go to closed loop Extravehicular activity ts going to be very
-i important; we are finding this to be more and more true as time goes on
All automated operations, the data system and the communication system,
_i_ must be very flexlble and adaptive. He w11l probably want distributed control
_ throughout the station so that we do net get locked Into 3ust one way of doing
_, things. Propulsion and fluid management particularly cryogenic fled manage-
i_i merit, wiT1 be--_mportant drivers in the space station design
At OAST, the Aeronautics and Space Technology Program has always had what
_ we choose to call a generic technology program. It ts sort of a "technologypush" program where you do things because the state of the technology indicates}-
that you are able to make certain advances That program has existed tn OAS1
and ts still there They have identified a certain part of that progra¢ that
__ ts contributory to the kinds of things that a space station might need. Beyond
that, the next step ls to define, from the generic program, a focused technol
ogy program that would be very specifically oriented toward advancing technol
- ogy for space station requirements.
=_ I have emphasized in the Steering Committee that the program should have
as tts output things that can specifically benefit a space station program In
tts Phase B as well as its Phase C and O activities. That technology ts not
]ust hardware It can be analysis and simulation; tt can be results of labora
tory tests, results of activity In test beds, ano even experimental flight
test programs
The technology flows from this focused program into a numberof areas, and
the products that comeout, again, are not Just hardware [n fact hardware ts
probably the least important thing that comesout of the technology program
Those things that people and organizations are going to need to do this _ob are
what Is important. And they need to happen on a schedule tltat wtll ftt tnto
the overall plan. So we must move forward quickly.
}: ?
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flgure 3 ' ! flow chart of how terhnology mlght develop from the requ_re-
I merits of the--%_ce station through the fOcuSed program. There are other ap-
proache_, _e way ts to cut through disciplines and say that you w111 make
proQres_ t_ ..awer, or in thermal, or on a_titude co_trol, etc. Another Is to
_.:+ look at something llke energy management, whtch t_ a combination of thermal and
power and can affect nearly all of the other technoloQtcal areas, lhis can
eye. be extended to structural technology, and to the attitude control system°
whack becomes tmpnrt_nt wtth very large arrays,
Weneed to integrate all of these activities so that we _ attention to
the most tmportafit parts of the technology tnvolved (fig. 4). 1he structures
people alone, for example, wtthout understanding what the power people need.,
may not produce the technology that best coincides with what ts needed In the
power area. So one actl_lty of the Steertng Committee Is to encourage this
type of Integration.
All of these Ideas flow tnto a sort of "bus" of technology (fig. 5) _hat
can then go lnto all areas of the development of the space stat._on -*_cludtrg
a very Important area. the evolution of the station beyond Its lnltt.J'_ c_pa-
' btllty, or a flexibility over ttme. This ts one of the problem,s it+ a _echnol-
_i++ ogy program: you can never be exactly sure where the benefits _,re..+_ng to
' ,, % t
-_, show up. Weare trytng to focus on the spectftc pro4_,_, ,+eed_ :or a space
=_ station.
• !i:
Now, 3_st a short discussion of a partlc._tar acttvtty that mtght be of
--_, tnterest to thts group. OAS1is plarmlng flight research as well as their
'_ traditional ground-based research. One element of that ts a voltage operating
_i., 1tmtt test, the VOLTProgram, for space testtng of photovolt_tc concepts A
-_: numberof people here knowmore about this than l do, but I would like to
_. mention It t, the context of this conference.
The tdea at OASTts to use the shuttle to conduct research In the space
environment In a numberof areas. In the VOLTsertes (fig. 6) there w111 be
four In-flight expprlments beginning In 1985, two tnstde the bay and two out-
" stde the bay; two are planar arrays and two are concentrator arrays. VOLT-1
and VOLT-3 use applted btas voltages; VOLI-2 and VOLT-4 use self-generated
. voltages. So the enttre structure has somesymmetry to tt. These experiments
.... are needed to obtain data from high-voltage planar and concentrator arrays,
"_ the 1den betng to produce design guidelines for large high-voltage arrays tn
_" low Earth orbtt, data on the 11mtts on operating voltage, a validated analyti-
cal tool for the ftnal designers of the space statton array, and a destgn
evaluation for these array technologies.
Figure 7 Illustrates the technology flow for the spectftc case of high-
voltage array destgn, Out of genertc technology and the focused program come
design data for the creatton of the fltght experiment. Out of the flight ex-
periment comedata that beneftt the space statton, and tt feeds back from the
space statton tnto the requirements area. One of the beauttes of the space
sttuttle Is that as we learn, we can repeat what we have done before and tmprove
on it. This ts _ust one example of how a technology program can flow Into
' f11ght testtng and eventually result In very spectftc products that improve
other programs, in particular the space station program.
_:i I thank you for your attention. Again, thank you for tnvlttng me here.
ir: 4
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SSTFREOUInEMENTS
TECItNOLOGYPROGRAMFOCUS
T"._ • ORIENTATION
e ![ATrlTUDEcoNTROLI • DISTURBANCES:i_ : . • FLEXIBILITY
_'. • MOMENTUM
-_ MGMT.
i_L-" CELLS
Lv • DYNAMICS
• • MECHANISMS BLANKETS • COATINGS
"'-' l STRUCI1L/RE • SUBSTRATE [P-0_ • HEAT SINKS
- CONDUCTANCE THERMAL
,._... . • MATERIALS • PLASMA : SHADOWING.....
: PROTECTION
! ,
• ORBII
[ ON.BOARDPROeULS,ONl : PRA. I I_HoTOvOLTAIC ARRAY1THRUSTERS • •
Figure5_-_--T-echnoloqytransfer.
i,,
VOLT-l: 1985 _ VOLT-2:1987
_ (EARLY} ,,
• BIASED PLANAR • PLANAR ARRAY
ARRAY SEGMENTS
(± 1000 VOLTS|. " * SELF-GENERATeD
VOLTAGES TO
\ J" _ 500.VOLTS ................
i
VOLT-3:1986 VOLT-l: 1887
• " (LATE)
• 81ASEO
CONCENTRATOR °CONCENTRATOR -
ARRAY SEGMENTS ARRAY
(_+1009 VOLTS) . _ ' • SELFGENERA_EDHIGHER
VOLTAGES
Figure6, - Voltageoperatinglimit tests.
/: TECHNOLOGIES FOCUS TESTS PRODUCTS
-,i ENVIRONMENTALINTERACTIONS
m_ HIGH VOLTAGE ARRAY
__ PERFORMANCE- / v,J,-, \ GUIDELINES
_ PHOTOVOLTAICS ( FLIGHT _T--_ FOR
_, PLASMA _ PROGRAM_ HV
INTERACTIONS _ PROGRAM_ /___
IMPACT ARRAYS
DEVELOPMENT
_. HV ARRAY TECItNOLOGY ,
-_ REQUIREMENT P_%_S
_' " SPACE STATION
Figure 7. - High-power, high-voltage photovoltaic array for space station.
t


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